Alternator and Regulator Circuit Test
Alternator and Regulator Circuit Test1. Be sure the battery is sufficiently charged and in good condition.
2. Raise the hoist to full height.
3. Hook up the ammeter, 0 - 400 A, to the starter sub-harness.
4. Lower the hoist.
5. Hook up the voltmeter, 0 - 20 V (accurate within 0.1 V), to T101.
6. Start the engine. Hold the engine at 3,000 rpm with no load (in Park or Neutral) until the radiator fan comes on then let it idle.
7. Raise the engine speed to 2,000 rpm, and hold it there.
8. Turn the headlights (high beam) on, and measure voltage at the under-hood fuse/relay box terminal.
Is the voltage between 13.9 and 15.1 V?
YES - Go to step 9.
NO - Repair or replace the alternator.
9. Read the amperage at 13.5 V.
NOTE: Adjust the voltage by turning the blower motor, rear window defogger, brake lights, etc. ON.
Is the amperage 60 A or more?
YES - Alternator/regulator operation is OK.
NO - Repair or replace the alternator.
Alternator Control System Test
1. Check for proper operation of the electrical load detector(ELD) by checking the malfunction indicator lamp (MIL).
2. Disconnect the engine wire harness 8P connector from the starter sub-harness 8P connector.
3. Start the engine, and turn the headlights (high beam) ON.
4. Measure voltage between the engine wire harness 8P connector terminal No.3 and the positive terminal of the battery.
Is there 1 V or less?
YES - Go to step 8.
NO - Go to step 5.
5. Turn the headlights and ignition switch OFF.
6. Disconnect the negative cable from the battery.
7. Disconnect engine control module (ECM)/ powertrain control module (PCM) connector B (24P).
8. Check for continuity between ECM/PCM connector terminal B18 and body ground.
Is there continuity?
YES - Repair short in the wire between the alternator and the ECM/PCM.
NO - Check that the terminals are firmly seated at the connector. If OK, substitute a known-good ECM/PCM, and recheck.
If the prescribed voltage is now available, replace the original ECM/PCM.
9. Turn the headlights and ignition switch OFF.
10. Disconnect ECM/PCM connector B (24P).
11. Check for continuity between ECM/PCM connector terminal B18 and engine wire harness 8P connector terminal No.3.
Is there continuity?
YES - Repair or replace the alternator.
NO - Repair open in the wire between the alternator and the ECM/PCM.